Assessment of safety and in situ antibacterial activity of Weissella cibaria strains isolated from dairy farms in Minas Gerais State, Brazil, for their food application.

Weissella cibaria W21, W25, and W42 strains have previously been characterized for their antagonism against a range of foodborne pathogens. However, prior to their use as protective agents, further analyses such as their safety and in situ activity are needed. The safety of W. cibaria W21, W25, and W42 strains was predicted in silico and confirmed experimentally. Analyses of their genomes using appropriate software did not reveal any acquired antimicrobial resistance genes, nor mobile genetic elements (MGEs). The survival of each strain was determined in vitro under conditions mimicking the gastrointestinal tract (GIT). Thus, hemolysis analysis was performed using blood agar and the cytotoxicity assay was determined using a mixture of two cell lines (80% of Caco-2 and 20% of HT-29). We also performed the inflammation and anti-inflammation capabilities of these strains using the promonocytic human cell line U937. The Weissella strains were found to be haemolysis-negative and non-cytotoxic and did not induce any inflammation. Furthermore, these strains adhered tightly to intestinal Caco-2 cell-lines and exerted in situ anti-proliferative activity against methicillin-resistant Staphylococcus aureus (strain MRSA S1) and Escherichia coli 181, a colistin-resistant strain. However, the W. cibaria strains showed low survival rate under simulated GIT conditions in vitro. The unusual LAB-strains W. cibaria strains W21, W25, and W42 are safe and endowed with potent antibacterial activities. These strains are therefore good candidates for industrial applications. The results of this study provide a characterization and insights into Weissella strains, which are considered unusual LAB, but which prompt a growing interest in their bio-functional properties and their potential industrial applications.

Genomic Analyses of Weissella cibaria W25, a Potential Bacteriocin-Producing Strain Isolated from Pasture in Campos das Vertentes, Minas Gerais, Brazil.

Weissella is a genus containing Gram-positive, heterofermentative bacteria belonging to the lactic acid bacteria (LAB) group. These bacteria are endowed with promising technological and antimicrobial attributes. Weissella cibaria W25 was isolated from a dairy environment where raw milk cheeses are produced. Therefore, we sequenced and assembled the W25 draft genome sequence, which consists of 41 contigs totaling ~2.4 Mbp, with a G + C content of 45.04%. Then we carried out a comprehensive comparative genomic analysis with W. cibaria 110, known to produce the weissellicin 110 bacteriocin, and four other non-bacteriocin-producing W. cibaria strains.

Weissella: An Emerging Bacterium with Promising Health Benefits.

Weissella strains have been the subject of much research over the last 5 years because of the genus' technological and probiotic potential. Certain strains have attracted the attention of the pharmaceutical, medical, and food industries because of their ability to produce antimicrobial exopolysaccharides (EPSs). Moreover, Weissella strains are able to keep foodborne pathogens in check because of the bacteriocins, hydrogen peroxide, and organic acids they can produce; all listed have recognized pathogen inhibitory activities. The Weissella genus has also shown potential for treating atopic dermatitis and certain cancers. W. cibaria, W. confusa, and W. paramesenteroides are particularly of note because of their probiotic potential (fermentation of prebiotic fibers) and their ability to survive in the gastrointestinal tract. It is important to note that most of the Weissella strains with these health-promoting properties have been shown to be save safe, due to the absence or the low occurrence of virulence or antibiotic-resistant genes. A large number of scientific studies continue to report on and to support the use of Weissella strains in the food and pharmaceutical industries. This review provides an overview of these studies and draws conclusions for future uses of this rich and previously unexplored genus.

Health beliefs towards kefir correlate with emotion and attitude: A study using an emoji scale in Brazil.

Emojis can be used to explore food-evoked emotions in order to provide information that can support the product development and marketing decisions. This study aimed to evaluate consumers' acceptance, purchase intent and emotional responses to milk beverages, with and without kefir added, before and after these consumers were informed about the products' composition (0%, 15%, 30% and 50% m/v) and health claims toward kefir (blind and informed tests, respectively). Emotional responses were assessed by emoji use within a RATA questionnaire in order quantify the perceived significance of the emojis chosen. In the informed test, the consumers' perception of the sensory attributes of the milk beverages, such as their perception of an acid taste in added kefir beverages was shown to have changed. Overall, participants attributed significantly higher acceptance and purchase intent scores to added kefir beverages after they had been informed on its health benefits. In addition, expressions of positive emotion increased when participants were exposed to stimuli related to health benefits of kefir (15%, 30% and 50% m/v), while negative expressions of emotion decreased. The provided information of kefir modified valence and arousal in subjects, and it can be said that to 30% of kefir can be added to yogurt without compromising its sensory acceptability. Thus, health benefits alone cannot improve product acceptance, since participants found a 50% addition of kefir to be unpleasant when tasted during a blind test. Mixed beverages may present a probiotic beverage alternative for consumers who dislike kefir milk, but want to include it in their diets. The implications of liking and purchase intent and how they are linked to emotions are discussed in this paper as well.

The ability of Lactococcus lactis subsp. lactis bv. diacetylactis strains in producing nisin.

Lactococcus lactis subsp. lactis bv. diacetylactis is a relevant microorganism for the dairy industry because of its role in the production of aromatic compounds. Despite this technological property, the identification of bacteriocinogenic potential of obtained strains can offer the additional positive aspect of biosafety. A panel of 15 L. lactis subsp. lactis bv. diacetylactis strains was characterised for the presence and expression of bacteriocin related genes, and further investigated regarding the nisin operon. Eight strains were positive only for nisA, and one strain (SBR4) presented a full nisin operon, with sequencing that was shown to be similar to nisin Z. Only SBR4 presented inhibitory activity against 16 microbial target strains. The growth curves of selected targets strains confirmed the inhibitory activity of SBR4 and consequently the nisin production. This research has demonstrated the inhibitory potential of L. lactis subsp. lactis bv. diacetylactis strain, SBR4, due to its ability to produce nisin Z. This biopreservative potential, associated to previously characterised technological properties, allow the indication of this strain as a promising candidate to be used by the dairy industry as a starter or adjunct culture.